The Food and Drug Administration is poised to approve the first genetically modified animal for human consumption, a highly anticipated decision that is stirring controversy and could mark a turning point in the way American food is produced.

FDA scientists gave a boost last week to the Massachusetts company that wants federal approval to market a genetically engineered salmon, declaring that the altered salmon is safe to eat and does not pose a threat to the environment.

“Food from AquAdvantage Salmon . . . is as safe to eat as food from other Atlantic salmon,” the FDA staff wrote in a briefing document.

Those findings will be presented Sept. 19 to a panel of scientific experts which will advise top officials at the FDA whether to approve the altered salmon. The panel is holding two days of meetings to hear from FDA staff, the company behind AquAdvantage and the public.

AquAdvantage is an Atlantic salmon that has been given a gene from the ocean pout, an eel-like fish, which allows the salmon to grow twice as fast as a traditional Atlantic salmon. It also contains a growth hormone from a Chinook salmon.

AquaBounty, the Massachusetts company that first applied to the FDA for permission to sell its fish in 1995, said the modified fish is identical to the Atlantic salmon, except for the speed of its growth.

“We’ve been studying this fish for more than 10 years,” said Ronald L. Stotish, the company’s president and chief executive. “In characteristics, physiology, behavior, this is an Atlantic salmon. It looks like an Atlantic salmon. It tastes like an Atlantic salmon.”

The team of scientists at the FDA that reviewed AquaBounty’s application seems to agree. “We have found no biologically relevant difference between food from [AquaBounty salmon] and conventional Atlantic salmon,” the briefing documents said.

But independent scientists, consumer groups and environmental organizations are concerned about both the pending decision and the process that the FDA uses to determine whether the genetically modified fish is safe for human health and the environment.